tracing/probe: Verify alloc_trace_*probe() result

Since alloc_trace_*probe() returns -EINVAL only if !event && !group,
it should not happen in trace_*probe_create(). If we catch that case
there is a bug. So use WARN_ON_ONCE() instead of pr_info().

Link: http://lkml.kernel.org/r/155253785078.14922.16902223633734601469.stgit@devnote2Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/trace_kprobe.c

@@ -693,9 +693,9 @@ static int trace_kprobe_create(int argc, const char *argv[])
 	tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
 			       argc, is_return);
 	if (IS_ERR(tk)) {
-		pr_info("Failed to allocate trace_probe.(%d)\n",
-			(int)PTR_ERR(tk));
 		ret = PTR_ERR(tk);
+		/* This must return -ENOMEM otherwise there is a bug */
+		WARN_ON_ONCE(ret != -ENOMEM);
 		goto out;
 	}
 

kernel/trace/trace_uprobe.c

@@ -514,8 +514,9 @@ static int trace_uprobe_create(int argc, const char **argv)
 
 	tu = alloc_trace_uprobe(group, event, argc, is_return);
 	if (IS_ERR(tu)) {
-		pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));
 		ret = PTR_ERR(tu);
+		/* This must return -ENOMEM otherwise there is a bug */
+		WARN_ON_ONCE(ret != -ENOMEM);
 		goto fail_address_parse;
 	}
 	tu->offset = offset;